I shoot a lightweight browning citori in 20g for quail and dove. It is an absolute joy to shoot and carry and more than enough fire power. I even thought of going down to to 28g.
For trap shooting, if you are doing it for fun it does not matter what you shoot. However, if you are shooting competitively and money is on the line, there is no question that a 12g is your choice. NO ONE shoots anything other than a 12g in competitive trap shooting. I am assuming you know the difference between trap and skeet since some incorrectly use the terms interchangeably. Shooting the small gauge in skeet is fun and goes all the way down to .410 in competitions.
Hard to give you guidance for trap since I do not know if you are just having fun or competitive. You can not hardly get the barrel of a good o/u trap gun for $1500. A good compromise if you are serious about shooting trap is a semi auto (trap grade) in 12g. If you get a trap semi make sure you know if you need to plug the gun for hunting.
Last edited by colbad; December 27, 2012 at 12:21 AM.